(1) Field of the Invention
The invention relates to elastomeric impulse energy storage and transfer systems, particularly as used in low-noise projectile launching systems.
(2) Description of the Prior Art
It is known to rapidly convert potential energy of a working fluid to kinetic energy for a projectile launch by means of ram pump and turbine pump ejection systems. Both systems are mechanically complex and tend to radiate noise into the surrounding fluid medium.
A ram pump type of energy storage and conversion system converts the potential energy of compressed air stored in a flask to kinetic energy by means of a piston assembly. The system requires a massive piston apparatus to transfer sufficient kinetic energy to a working fluid to launch a projectile. The mechanical friction and the mass of the piston act to reduce system efficiency and to produce substantial radiated noise. The ram pump system includes numerous mechanical components, in addition to the piston assembly, which require frequent maintenance.
A turbine pump type energy storage and conversion system converts potential energy of compressed air stored in a flask to kinetic energy of a working fluid by the cooperative interaction of three major components: an air turbine, a speed reduction unit, and a rotary impeller pump. The turbine system further requires a complex high-speed air turbine drive inlet and a complex low cavitation impeller pump. The turbine system thus is costly. Because of the dynamic interaction of system components, the turbine system tends to be noisy. In addition, overall system efficiency is quite low because of mechanical losses.
In U.S. Pat. No. 4,848,210, issued Jul. 18, 1989 to Laurent C. Bissonnette, there is shown and described an impulse energy storage and transfer system having as a principal component thereof an elastomeric energy storage device. The elastomeric device is adapted to accept and store a working fluid. In accepting the working fluid, the elastomeric means, a bladder-type accumulator, becomes distended. Upon opening of the accumulator for egress of the working fluid, the stored energy is rapidly converted into kinetic energy for quietly ejecting a projectile, along with the stored fluid, from the system and into a surrounding medium. The accumulator used in the '210 system is substantially spherical.
While the '210 system has demonstrated marked improvement over the prior ram pump and turbine pump types of systems, there remain problem areas. As the spherical accumulator discharges the working fluid, typically a liquid, such as water, the collapsing accumulator reaches a point in its configuration transition in which the stored medium flows erratically from the accumulator and creates an audible noise. It is beneficial to have a smooth and even flow of working fluid from the accumulator and to eliminate any noises emanating therefrom.